A decade of restrictions on chemicals used in flame retardants have paid off for wildlife and humans living in and around the San Francisco Bay, according to a study published Sunday.

In 2003, California started regulating certain chemicals used to prevent furniture and household items from burning. While the bay once charted the highest worldwide pollution levels of the toxin, a sharp decline has been reported in the bay's birds, shellfish and fish, the San Francisco Chronicle -- KCRA 3's content-sharing partner -- reported.

"This is quite a success story," said Rebecca Sutton, the study's lead author and a senior scientist at the San Francisco Estuary Institute. "We tie these results directly to the phaseout."

Manufacturers used the chemicals - called Polybrominated Diphenyl Ethers, or PBDEs - as a cheap way to meet flammability standards, the newspaper reported. They had been widely used since the 1970s.

The toxins are ingested when people breathe in household dust, and they enter the environment when items made with the chemicals degrade and wash into natural bodies of water where wildlife live, says the study published in the journal Environmental Science and Technology.

Myrto Petreas of the California Department of Toxic Substances Control found in separate research 15 years ago that Bay Area women had levels of the toxins about 10 times higher than women in Europe. Petreas was not part of the most recent study.

In pregnant women, the toxins may cause babies to have lower IQs, attention-deficit disorder and hyperactivity, researchers have found.

The new study found that the banned toxins have declined in the bay's muscles by up to 95 percent. It's also less common in blood taken from women at San Francisco General Hospital, researchers say.

"The ban works," Petreas said. "Manufacturers are not using PBDEs."

Despite the ban, manufacturers continue to innovate new and potentially harmful types of fire retardants, said Arlene Blum, executive director of the Berkeley-based Green Science Policy Institute. "Industry wants to find another chemical as similar as possible," she said. "That leads to regrettable substitutions."